So my stripboard arduino clone can do something useful I've built some shields for it. This one is a dual function board handling i2c (both 3.3 & 5 volt) and access to a microSD card via the SPI bus.

The i2c bus is physically accessed by the pins at the bottom of the picture above. On the left is the 5 volt pins (the 4x4 block) and on the right is the 3.3 volt ones (I've run out of pin headers so only one column is populated). Each column on both sides provides v+, SDA, SCL and ground.

The red sub-board is a sparkfun logic level converter that handles the conversion for the 3.3 volt part of the i2c bus. Unlike i2c, the lines on the SPI bus are unidirectional so I could use voltage dividers to perform the level conversion instead of the larger footprint sparkfun board.

I've used an old SD to microSD adapter as a card socket which was easy to work with as the contact spacing is the same as standard pin headers (see the top of the first picture).

The underside of the board is a bit less neat than I would like although I'm quite pleased with how the vertical solder tracks for the SD card came out.

Right now I'm using the 5v i2c bus to read from an SRF08 ranger mounted on the bottom of my prototype UAV, and the SD card to dump the values of the sensors and internal state of relevant program parameters for post test analysis. I'm going to use the 3.3v i2c bus to read from the bma180 and itg3200 once I've mounted both of them on to the UAV chassis.

Arduino code here.

04/Sep/11 - Updated with eagle schematic below - yellow horizontal lines are the copper tracks on the underside of the stripboard, red lines are jumper wires on the top.